9" axle ?'s

[jguajardotx]

My third member gave out on me recentley so I found a descent one and bought it. Problem is when I installed it and put the axles in they wont grip or turn just metal rubbing against metal. I take it I bought the wrong spline count from what I had huh? Even though I was told it was the same. Do I need to purchase new axles to fit the new third member now and how the heck do I know what spline count I got? Any possibility I can do this without having to take thrid member off?

[averagef250]

May be able to switch side gears in the carrier.

[jguajardotx]

Are there only two types of splines though 28 & 31? If so I guess I could try looking for some axles that work for the 31.